Is a gap in roof sheathing at the ridge okay before shingling?
Roof sheathing gaps can cause thermal expansion issues and shingle telegraphing where the decking seam shows through once warmed up. Leaving these gaps unclosed risks damaging the life of the roof over time, though fixes like ripping a piece of CDX plywood on a table saw are sometimes considered.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 41.8× more often in r/Roofing than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
Is a gap in roof sheathing at the ridge okay before shingling?
- 1leaving the gap as isDid this help you?
- 2filling the gap with cdx ripped on a table sawDid this help you?
- 3running ridge vent meshDid this help you?
- 4cutting back the sheathing further for a ridge ventDid this help you?
- 5Installing shingles directly over plank decking without adding sheathing to save moneyDid this help you?
- 6Pulling bad nails and putting down membrane before shingling over planksDid this help you?
- 7Adding plywood or OSB sheathing over the planks to qualify for manufacturer and workmanship warrantiesDid this help you?
- 8Going over the old plank deck with OSB instead of trying to patch the rotDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Extended my eaves out a few inches and now have a funky seam at my ridge, is this gap acceptable before shingling? If not how should I close the gap, just rip some cdx on my table saw?”source ↗
“New roof was finished last week. Just noticed today that I seem to be getting significantly thermal expansion and shingles telegraphing the decking gap underneath? Once it cools down, it’s not visible, but it can’t be good for the life of the roof?”source ↗
“I have a house we think is either 68 or 72, which we got 12 years ago. The roof has always leaked in various places, different every time. But a recent storm started leaking directly onto the attic hatch so I stuck a flashlight in there and I could see that the original nails were rusted down to toothpicks and the rain was going in through those holes.”source ↗
“The last guy had a look and said the planks actually look fine and he didn't think that they would need to do anything more than pull the bad nails, put down membrane and then shingle it.”source ↗
“When the manufacturer is not warrantying the roof - you can install over planks as long as you meet a long list of impossible criteria.”source ↗
“When the manufacturer sells you a premium warranty where they warranty the roof and hte workmanship... they require the roof to be sheathed.”source ↗
“So I tore off my shingle roof today and I've got an older house so it has a plank deck. It's rotten in spots, splitting, and has some pretty bad gaps. My plan is to just go over the whole thing with 5/8 OSB but I was wondering if there is anything I need to make sure I do? Also do I need H clips?”source ↗